diff --git a/CHANGELOG.md b/CHANGELOG.md
index ed7a066..e6bf181 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,39 @@
 
 All notable changes to this project will be documented in this file.
 
+## 0.5.0 - 2026-09-08
+
+### Breaking Changes
+
+- feat!: name the unknown key, expose tail probabilities, flag short fits
+- refactor!: remove the factor-graph surface nothing used, add try_winner
+
+### Bug Fixes
+
+- fix(test): the ingestion-order property was comparing two truncated fits
+
+### Documentation
+
+- docs: record that the event log is the source of truth, and why
+
+### Features
+
+- feat: add UnknownKeys::Prior, and explain why there is no Skip
+- feat: add History::posterior_of for a linear combination of competitors
+- feat: add History::predict_margin for scored matchups
+- feat: add expected_variance_reduction for scored active learning
+
+### Styling
+
+- style: factor the event-pair type out of the reconvergence fixture
+- style: use arrays rather than vec! in the calibration fixture
+
+### Testing
+
+- test: pin that re-convergence is path-independent
+- test: calibrate the marginals against the exact posterior
+- test: pin what an additive model does to combined uncertainty
+
 ## 0.4.2 - 2026-09-07
 
 ### Bug Fixes
@@ -9,6 +42,10 @@ All notable changes to this project will be documented in this file.
 - fix: replace the erfc approximation with libm, for free
 - fix: route every transcendental through libm, and combine sigmas with hypot
 
+### Miscellaneous Tasks
+
+- chore: Release trueskill-tt version 0.4.2
+
 ### Testing
 
 - test: localise the erfc_inv tail residual to the caller's argument
diff --git a/Cargo.toml b/Cargo.toml
index 4439870..14b681e 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "trueskill-tt"
-version = "0.4.2"
+version = "0.5.0"
 edition = "2024"
 rust-version = "1.85"
 description = "TrueSkill Through Time: Bayesian skill rating that tracks how skill evolves over time, via Gaussian message passing"